Door lock with safety release

ABSTRACT

A lock structure for an upwardly acting door of a truck van wherein a latch bolt and a manually engageable actuating member are pivotally mounted upon the door for movement about an axis substantially perpendicular to the plane of the door when it is in the closed position. The latch bolt has an elongated arcuate hook portion adapted to extend below the lower edge of the door for engagement with a catch mounted on the truck bed. The latch bolt is urged by gravity to move more securely into the latched position. The latch bolt and actuating member are pivotally mounted on a mounting plate which is releasably secured to the external side of the door by a releasable coupling device accessible solely from the inside of the door, even though the latch bolt is initially engaged with the catch. The actuating member coacts with a keeper device mounted on the door and, when connected thereto, as by a padlock, maintains the latching mechanism connected to the door even after the coupling device has been released.

United States Patent 1191 Galbreath et al. V

DOOR LOCK WITH SAFETY RELEASE lnventorsi Gerald W. Galbreath; Alfred T.

Dietrich; George Mosbarger, allof Marion, Ohio Overhead Door Corporation, Dallas, Tex.

Filed: Dec. 27, 1971 Appl. No.: 212,714

[73] Assignee:

u.s.;c1 292/100, 292/104, 292/108, 292/1310. 29, 292/1910. 53, 292 1310. 65,

292/240 Int. Cl. E05c 3/26 [58] Field of Search292/DIG.29, DIG; 53, DIG. 65,

, T References Cited UNITED STATES PATENTS ll/l97l Rosehitz et a1. 292/240 9/l966 Sprung...-. 70/93 X Primary E.\'amine'f -Richard E. Moore 1 Attorney, Agent, 0rlFirmWoodhams,'Blanchard and 1451 Apr. 9, 1974 5 7 ABSTRACT A lock structure for an upwardly acting door of a truck van wherein a latch bolt and a manually engageable actuating member are pivotally mounted upon the door for movement about an axis substantially perpendicular to the plane 'of the door when it is in the 1 closed position. The latch bolt has an elongated arcuate hook portion adapted to extend below the lower edge of the door for engagement with a catch mounted on the truck bed. The latch bolt is urged by gravity to move more securely into the latched position. The latch bolt and actuating member are pivotally mounted on a mounting plate which is releasably secured to the external side of the door by a releasable coupling device accessible solely from the inside of the door, even though the latch bolt is initially engaged with the catch. The actuating member coacts V with a keeper device mounted on the door and, when connected thereto, as by a padlock, maintains the latching mechanism connected to the door even after the coupling device has been released.

1 T 7 Clairns, 6 Drawing Figure;

PATENTEDAPR 91m SHEET 2 (If 2 I 1 noon LocK'wrrn SAFETY RELEASE CROSS-REFERENCE TO RELATED APPLICATION This application is related to application Ser. No. 565, filed Mar. 18, 1970, and entitled Gravity Actuated Lock.

FIELD OF THE INVENTION This invention relates in general to a lock structure for an upwardly acting truck door and, more specifically, to a lock structure provided with a releasable mounting structure which is accessible solely from the interior of the truck van to disengage the lock structure from the door to permit opening of the door from the interior of the van, even though the door is locked on the outside. I

BACKGROUND OF THE INVENTION Application Ser. No. 20,565 describes a highly acceptable lock structure for truck doors, particularly for upwardly acting, horizontally sectioned doors. Although this lock structure is highly satisfactory, it can notbe openedfrom'within the truck van by a person accidentally trapped inside of the van. Although being trapped within a truck van is usually only an inconvenience and would not ordinarily present any threat to the life of a person so trapped, the situation is radically different in the case, for example, of refrigerated trucks using expandable gas, such as a nitrogen system. Thus, if a person is trapped within a truck van, when the gas systemis operating, the trapped person would rapidly suffocate or freeze to death if there was no way of opening the door from inside the van.

To overcome the above problem, U. S. Pat. No. 3,352,585, owned by the Assignee of this application, describes a door lock having a safety release device associated therewith for permitting the door lock to be unlatched from the interior of the truck van. While the safety lock structure disclosed in this patent has proven highly acceptable, nevertheless it was felt that both the structure and mode of operation of the safety release device of this patent could be significantly improved. For example, in the lock structure, of the abovementioned patent, when thesafety release device is actuated to permit opening of thedoor from inside the truck van, the complete door latch structure is disconnected from the door which, in some circumstances,

may result in the door lock structure being accidentally lost or misplaced.

Accordingly, it is an object of this invention to provide an improved door lock structure for an upwardly acting truck door wherein the door lock structure may be rapidly opened from within the closed truck van to permit a person locked within the truck van to unlock the door and open same.

A further object of this invention is the provision of a lock structure, as aforesaid, having a safety release device associated therewith and positioned on the inside of the door for permitting manual actuation of same solely from the interior of the truck van.

A further object of this invention is the provision of a lock structure, as aforesaid, wherein the safety release device includes a releasable coupling extending through the door and coacting with the latch assembly disposed on the external side of the door, which releasable coupling normally maintainsthe latch assembly fixedly connected to the door but permits the latch assembly to be easily disconnected, at least partially, from .the door-to permit opening of the latched door from the interior of the van.

A further object of this invention is to provide a latch assembly or structure, as aforesaid, which remains partially coupled to the door, such as through a padlock or safety chain, even after'the safety release mechanism has been manually actuated so that the latch assembly will not obstruct opening of tile door but will still remain connected to the door, thereby avoiding loss of the latch assembly and greatly facilitating the reassem bly of the latch assembly on the door.

A further object of this invention is to provide an improved door lock structure, as aforesaid, which is characterized by its simplicity and economy of construction, manufacture and use.

Other objects and purposes of this invention will be apparent to persons familiar with lock structures of this type upon reading the following specification and inspecting the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a broken, fragmentary front elevational view of a truck door and an adjacent portion of a truck bed including the lock structure embodying the invention, as viewed from the exterior of the truck and illustrating the lock structure in the locked position.

FIG. 2 is a fragmentary cross-sectional view taken along the line II-II of FIG. 1.

FIG. 3 is an elevational view of the embodiment of FIGS. 1 and 2 as viewed from the interior of the truck van.

FIG. 4 is a fragmentary front elevational view similar to FIG. 1 except that the door is shown inapartially raised position after the safety mechanism has beenrelased. I

FIG. 5 is a fragmentary cross-sectional view taken substantially along the line VV of FIG. 4.

FIG. 6 is an elevational view illustrating the interior side of the truck door after the safety mechanism has been released. v

Certain terminology will be used in the following descriptionfor conveniencein reference only. For example, the words up, down,left and right will have reference to directions in the drawings to which reference is made. The word front will have reference to the exterior side of the lock structure as viewed I from the rear of the truck van and as appearing in FIG. 1, whereas the word rear will refer to the side of the lock structure disposed adjacent the interior of the truck van, such as illustrated in FIG. 4. The terms inner and outer will refer to directions toward and away from the geometric center of the device and designated parts thereof. Said terminology will include the words above specifically mentioned, derivatives thereof, and words of similar import.

SUMMARY OF THE INVENTION The objects and purposes of the invention, including those set forth above, have been met by providing a lock structure including catch means mounted on the bed of the truck or similar vehicle and a latch assembly mounted upon the lower end of an' upwardly acting door of the truck van. The latch assembly has a latch bolt and actuating member which are pivotally connected to a mounting plate which is secured to the external surface of the door by releasable coupling means.' The latch bolt has an elongated hook portion having a cammed inner surface engageable with the catch means. The latch bolt is pivotally mounted upon the door and is moved into'a latched position by an actuating member which is held in its latching position by a first keeper. Gravity also opposes the release of the latch bolt from its latched position. The actuating member is held away from its latched position by a sec ond keeper. The coupling means, which normally secures the mounting plate fixedly to the door, extends through the door and is connected to a manual actuating device mounted on the interior side of the door to effect disengagement of the mounting plate from the door by a person locked within the truck van. However, after the mounting plate has been released from the door, the lock structure remains connected to the door by a safety device, such as a padlock, connected between the first keeper and the actuating member.

DETAILED DESCRIPTION The door lock structure of the invention, a preferred embodiment of which is disclosed in FIG. 1, is comprised of a latch assembly 11' mounted upon the lower end of an upwardly acting door 12 and disposed for engagement with a catch assembly 13 that is mounted in the bed 14 of an otherwise substantially conventional truck van, of which the door 12 is a part. In this particular embodiment, the door 12 is comprised of a plurality of horizontally hinged sections 16 which are disposed in a substantially vertical plane when the door isclosed, and in a substantially horizon tal plane near the roof of the van when the door is open. A resiliently flexible weather seal 17 (FIG. 2) is mounted on the lower edge of the door 12 and is engageable with the bed 14 in a conventional manner.

The catch'assembly 13 (FIGS. 1 and 2) is comprised of an elongated, substantially rectangular casing 18 which is preferably fabricated from sheet or plate steel to form a top flange 19, a pair of sidewalls 21 and a pair of end walls 22. The sidewalls 21 and the end walls 22 define a catch chamber 23. A catch pin 24 is secured to and extends between the sidewalls 21 about midway between the end walls 22.

The'latch assembly 11 has a mounting plate 25 releasably secured to the exterior surface of the door 12 adjacent the lower edge thereof. A base plate 26 is positioned adjacent and fixedly connected to the mounting plate 25, as by welding. Base plate 26 supports an axle -27 which has an end portion of reduced diameter extending through an opening in the base plate 26 and rigidly secured thereto by means such as welding.

A manually operated lever or actuating member 28, which'is rotatably supported on axle 27, is comprised of a housing 29 having a front wall 31 (FIG. 2) and a rear wall 32 which are interconnected by aperipheral wall 33 having a substantial opening 34 (FIG. 1)

. formed therein. Said opening 34 is along the lower side of the housing 29 when the member 28 is in the latching position of FIG. 1. The front wall 31 and rear wall 32 of housing 29 have coaxial openings through which the axle 27 extends to pivotally support the actuating member 28. The actuating member 28 also has an integral arm or handle 36 which projects from the housing 29 lengthwise thereof and substantially radially of the axle 27.

I A latch bolt 37 has a shank 38 which is rotatably supported at its upper end upon the axle 27, and an elon- V gated arcuate hook 39 integral with the outer end of the shank 38 and having a slightly cammed inner sur- 5 jacent the free end of the hook 39. The center of gravity of the latch bolt 37, when it is pivotally supported by axle 27, is in the hook 49 near the shank 48. Thus, gravity urges latch bolt 37 into its locked position of FIG. 1. However, the edge 42 of the peripheral wall 33 limits movement of bolt 37 in a latching direction, and the edge 43 limits'movement of the bolt '37 in the opposite direction relative to the lever 28. The peripheral wall 33 also has a radially projecting, integral flange 44 adjacent the'edge 43.

An unlatched keeper 46 is pivotally mounted upon a pivot pin 47 which is rigidly secured to the mounting plate 25 near the housing 29. The keeper 46 has a cam surface 48 on its upper end and a hook 49 near to and below the surface 48. The keeper 46 has a counterbalance 51 which extends in the opposite radial direction from teh hook 49 relative to the pin 47. The counterbalance tends to move into a depending position whereby flange 44 will strike the cammed edge 48 above the hook 49 as the lever 28 is moved into its fully unlatched position. This engagement of keeper 46pivots same counterclockwise in FIG. 1 so that the flange 44 can move below the hook 49, after which the force of gravity, acting on the counterbalance 51, pivots the hook 49 into engagement with said flange 44 whereby the lever 28 and bolt 37 are held in the unlatched position.

A latched keeper 53 is sleeved upon a pivot pin 54. The pivot pin 54 is rigidly secured to a support plate 56 which is riveted directly to the door 12. A downwardly and frontwardly projecting flange 57 is located at the outer end of the arm 28 and is positioned adjacent a lug 58 on the keeper 53 when said keeper is suspended y from the pivot pin 54 and the lever 28 is in its latching position. The flange 57 and lug 58, when the latch assembly 11 is in its latched position of FIG. 1, have aligned openings for reception of a locking element, such as a conventional padlock 59 or a sealing band (not shown).

The keeper 53 has an arcuate edge flange 61 (FIG. 1) which extends over and is engageable by the upper edge of the flange 57 when the keeper 53 is in its normal depending position. Accordingly, if the latch bolt 37 should accidentally tend to work loose from the catch pin 24, due to irregular movements of the truck, for example, the arcuate flange 61 in the path of the projection 57 will positively prevent the actuating member 28 from rotating in a counterclockwise direction (FIG. 1) so that the disengagement of the bolt 37 from the pin 24 is positively prevented.

When the arm 28 is returned from its unlatched position to. its latching position of FIG. 1, the flange 57 strikes the upper flange 62 of the keeper 53 on the leftward side of the pivotpin 54 and thereby pivots the keeper 53 in a counterclockwise direction (FIG. 1) until the flange 57 reaches a position below the arcuate flange 61, whereupon the keeper 53 will swing under the force of gravity into its FIG. 1 position and thereby block upward movement of the flange 57, hence the arm 28.

The length and radius of the arcuate flange 61 are preferably selected so that the flange 61 cannot be moved away from a position obstructing the upward movement of theflange 57 when a conventional sealing band or padlock 59 is passed through the aligned openings in flange 57 and lug 58.

The support plate 56 has an integral stop 63 which projects outwardly'therefrom adjacent the inner side of the flange 57. The outer end of the handle 36 has a rearwardly opening recess 64 (FIG. 1) into which the stop 63 extends when the lever 28 is in its latched position.

' The latch assembly 11, as described above, substantially corresponds to the latched structure disclosed in copening application Ser. No. 20,565, and thus further description thereof is not believed necessary.

Considering now the manner in which the latch assembly 11 is secured to the door 12, there'is provided a retainer plate 66 which is positioned adjacent the exterior surface of the door and is fixedly secured to the door by conventional means, such as screws or rivets 67. The retainer plate 66 has an upper row of guide pins 68 and opposed side rows of guide pins 69 and 71 fixedly secured thereto for defining a confining structure positioned to surround three sides of the mounting plate 25. The guide pins 68, 69 and 71 are all identical and include a shank portion '72 (FIG. 5) fixedly'secured to the retainer plate 66 and projecting outwardly therefrom, which shank portion 72 has an enlarged head 73 formed on its free end. The head 73 is spaced from the front surface of the retainer plate 66 by a distance slightly greater than the thickness of the mounting plate 25, whereby the edge of the mounting plate is thus adapted to be slidably positioned under the head 73 substantially in abutting engagement with the shank 72 as illustrated in FIG. 2. Further, as illustrated in FIG. 4, the opposed rows of pins 69 and 71 diverge at a small angle relative to one another as they extend downwardly toward the truck bed.-

The mounting plate 25 is designed to coact with the guide pins mounted on the retainer plate 66 and, for this purpose, the mounting plate 25 has a substantially trapezoidal shape to permit it to be slidably moved upwardlyinto engagement with the pins 68, 69 and 71. The mounting plate 25 specifically includes an upper edge 76 which is adapted to abut the upper row of guide pins 68. The mounting plate 25 also has opposed tapered side edges 78 and 79 which arepositioned to abuttingly engage the side rows of guide pins 69 and 71, respectively. 7

To fixedly secure the mounting plate 25 to the door 12, there is provided a releasable coupling device 81 which, as illustrated in FIG. 2, includes a sleeve 83 disposed within an opening 82 formed within and extending through the door 12. A lock pin 84 is disposed within and extends through the sleeve 83, with the rearward end of the lock pin being slidably supported on a plate 86 which is fixedly secured to the inner end of the sleeve 83. The forward end ,of the lock pin 84 is slidably supported within and extends through suitable openings 8'7 and 88 formed in the retainer plate 66 and the mounting plate 25, respectively. A suitable cap 89 is fixedly connected, as by welding, over the forward end of the opening 88 for closing the opening to thereby prevent the pin 84 from being accessible exteriorly of the truck van.

The pin 84 is provided with a compression spring 91 in surrounding relationship therewith, which spring coacts between the plate 86 and a flange 92 secured to thelock pin, whereby the spring 91 resiliently urges the lock pin 84 forwardly (leftwardly in FIG. 2) so that same extends through the aligned openings 87 and 88 for fixedly retaining the mounting plate 25 locked in a position wherein its three'edges 76, 78 and 79 are re tained under the heads of the guide pins 68, 69 and 71, respectively.

To permit the coupling device 81 to be released, there is provided a manual release mechanism 93 positioned adjacent the interior side of the door 12, whereby same is thus accessible from the interior of the truck van. The manual release mechanism 93 includes an elongated handle or lever 94 which has a forklike end portion straddling the inner end of the'locking pin 84 and pivotally connected thereto by means of a pivot pin 96. The handle 94, which is mounted for swinging movement within a substantially horizontal plane, is normally disposed when in its storage position within a recess 97 formed within a mounting member 98 which is secured to the inner surface of the door 12. A fixed flange 99 projects outwardly into the recess 97, with the flange 99 and handle 94 having openings therethrough which are substantially aligned with one another when the'handle'is in the storage position illustrated in FIG. 3, whereby a suitable sealing band 101 can be threaded through the aligned openings.

The handle 94 is provided on the forked end thereof with portions 102 which project beyond the pivot pin 96 and function as cams, whereby when the handle 94 posed substantially'parallel'to the door, to a use position, wherein itextends substantially perpendicular to the plane of the door, the projecting cams 102 bear against the plate 86 and cause the: pin 84 to be pulled inwardly (rightwardly in FIGv 2) into the interior of the truck vanto thus withdraw the outer end of the pin from the opening 88 formed in the mounting plate 25.

The door 12 is also provided with a conventional lift handle 103 pivotally mounted on the interior surface thereof, which lift handle 103 is generally mounted closely adjacent but above the manual release mechanism 93 to thus permit a person within the truck van interior to manually grasp both the handle 94 and the h andle'l03 at the same time. t m

' OPERATION Although the operation of the door structure 10 will be apparent to a skilled person by reference to the foregoing description, it will be summarized briefly hereinafter.

Assuming that the latch assembly 11 is initially in its unlatched position (not shown) wherein the flange 44 of lever 28 is engaged beneaththe hook 49 of the keeper 46, then the keeper 46 will be manually swung (counterclockwise in FIG. 1) to release the flange 44. Actuating lever 28 will then be swung toward, its latched position (clockwise in FIG. 1), which will cause edge 43 to engage the latch bolt 37 to thus also swing the latch bolt towards a position of engagement with the catch pin 24. Since the upper surface 41 of book 39 is cammed, the free end thereof passes easily beneath the catch pin 24 until the surface 41 firmly engages the pin. As the handle 36 is moved into its latched position of FIG. 1, engagement of the hook shank 38 by the edge 43 insures a firm engagement of the cam surface 51 with the catch pin 24. Thereafter, should the door 12 be jarred or shifted downwardly, as during operation of the truck, gravity urges the latch bolt 37 in a clockwise direction thereby taking up any slack that may develop between the surface 41 and the pin 24.

As the latch assembly moves into its latched position, the handle flange 57 engages the keeper flange 62 and pivots the keeper 53 in a counterclockwise direction about the pivot pin 54 until the handle flange 57 can move past the keeper so as to engage the stop 63. The keeper 53 then swings in the opposite direction (clockwise in FIG. 1) so that the arcuate flange 61 moves back into a position wherein it is disposed directly above the upper end of the handle 36, whereby the keeper lug 58 is then disposed directly adjacent the handle flange 57. A suitable connecting device, such as a sealing band or a padlock 59, can then be inserted through the openings in the flange 57 and lug 58 to thus fixedly secure the actuating lever 28 in the latched po sition. 7

When it is desired to release the latch assembly 11 from its latched position, the keeper 53 is manually swung (counterclockwise in FIG. 1) to move arcuate flange 61 away from the handle 36, whereupon the handle 36 can then be manually swung (counterclockwise in FIG. 1) away from keeper 53 toward the keeper 46. This swinging of handle 36 causes edge 42 to engage the latch bolt 37 to thus move same out from beneath the catch pin 24. When handle 36 approaches the keeper 46, the flange 44 strikes the cam surface 48 causing the keeper 46 to swing in a counterclockwise direction, whereupon the flange 44 passes under the hook 49, whereby counterbalance 51 causes the keeper 46 to swing back in a clockwise direction to position the hook 49 over the flange 44 to thus hold the actuating member 28 and latch bolt 37 in a released position.

I the van due to the provision of the release mechanism 93 and the releasable coupling device 81. Referring particularly to FIGS. 2 and 3, the person in this situation, located within the tight interior of the truck van, would initially break the seal 101 to thus release the handle 94 from the flange 99. The handle 94 is then manually grasped and pivoted horizontally away from the inner surface of the door, which pivoting of the handle continues until the handle is substantially transverse to the door as illustrated in FIG. 5. As the handle 94 is pivotally swung into the released position of FIG. 5, the elongated cam projections 102 bear against the stationary plate 86, thereby causing the lock pin 84 to be drawn inwardly toward the-exterior of the van in opposition to the urging of spring 91'. This thus causes the outer end of the pin 84 to be axially withdrawn from the opening 88 formed in the mounting plate 25, the pin being withdrawn to assume the position substantially as illustrated in FIG. 5. The withdrawal of pin 84 from opening 88 thus releases the mounting pin 25 from the retainer plate 66. Accordingly, the person within the truck van can then grasp the handle 103 and lift the door 12 upwardly away from the bed 14. However, since the hook 39 is still disposed below the catch pin 24, the initial upward lifting of the door 12 will cause the mounting plate 25 to be relatively slidably moved downwardly from beneath the guide pins 68, 69 and 71, until the mounting plate 25 is totally released from the retainer plate 66 substantially as'illustrated in FIGS. 4 and 5. However, since the handle flange 57 is still connected to the keeper lug 58 by the padlock 59, the latch assembly does not become totally disconnected from the door, but remains connected to the door due to the padlock 59. Further, if necessary sufficient space exists between the bottom of the door 12 and the bed 14 to enable the person within the truck van to reach around and manually grip the hook bolt 37 to swing same out from beneath the catch pin 24 in the event the catch bolt does not totally disengage the catch pin during the initial upward lifting of the door. After the catch bolt 37 has totally disengaged the catch pin 24, the door 12 can then be moved into its fully open position, carrying with it the majority of the latch assembly due to the provision of the padlock 59, whereby the person can then freely exit the van.

Since the keeper 53 is mounted directly to the truck door, rather than on the mounting plate 25, the latch assembly thus remains connected to the door even when the coupling device 81 has been released, assuming that a padlock 59 or other suitable connecting element has been used to join flange 57 and lug 58. This thus prevents the latch device from being accidentally lost or misplaced, and greatly simplifies the remounting of the latch device, particularly the mounting plate 25, on the retainer plate 66. To remount the latch assembly, it is only necessary to slidably reposition the mounting plate 25 under the guide pins 68, 69 and 71. The handle 93 is then moved into its storage position of FIG. 3, whereuponthe spring 91 urges the pin 84 outwardly through the openings 87 and 88, thereby fixedly connecting the mounting plate 25 to the retainer plate 66.

While the invention as described utilizes a padlock 59 for interconnecting the coacting flanges on the handle and keeper, it will be readily apparent that numerous other devices, such as a chain or sealing band, could be utilized for this purpose.

Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosedapparatus, including the rearrangement of parts, lie within the scope of the present invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as folthereof, said latch means including mounting plate means'disposed adjacent said one side of said door, and an actuating member and a latch bolt pivotally mounted on said mounting plate means;

said latch means further including retainer means fixedly secured to said door adjacent said one side thereof, said retainer means having means having integral guide means positioned for engagement with said mounting plate means for preventing movement of said mounting plate means relative to said retainer means in all directions except downwardly;

catch means adapted to be mounted on the bed of a truck and positioned for engagement with said latch bolt when the lower edge of said door is adjacent said bed and said catch means;

releasable coupling means movably carried by said door for normally connecting said mounting plate means to said door, said releasable coupling means being normally positioned for holding said mounting plate means against said downward movement when said mounting plate means is in said position of engagement with said guide means;

release meansaccessible only from the otherside of said door and connected to said coupling means for selectively disengaging said coupling means from said mounting plate means to disconnect said mounting plate means from said door, whereby said door may be moved toward an open position without prior disconnection of said latch means from said catch means, said release means includ ing a lever handle pivotally mounted at said other side of said door and disposed for swinging movement within a plane substantially perpendicularto said door; and means loosely and securely connecting said latch means to said door after said mounting plate means near one end to the other end of said pin, said handle having cam means formed on the one end thereof and disposed for engagement with said other side of said door for retracting said pin from said aligned apertures in response to said swinging movement thereof from a first position disposed substantially parallel to the inner surface of the door to a second position disposed substantially perpendicular to the inner surface of the door.

3. in a truck van having a bed and an upwardly acting door, and a door lock structure coacting between the door and the bed, the door lock structure having an actuating member pivotally mounted on the door near the lower edge thereof for movement about a substantially horizontal pivot axis, a latch bolt pivotally supported upon the door for movement with respect to'said actuating member, saidlatch bolt having a shank and an elongated arcuate hook means extending sidewardly from the shank and adapted to extend below the lower edge of said door, the center of gravity of said bolt being near said shank, the radially inner surface of said hook means near the free end thereof being spaced radially from the latch bolt pivot axis by a distance slightly greater than the opposite end of said surface, catch means mounted to said bed below said pivot axis and arranged for snug engagement by said surface of said hook means while said center of gravity is spaced from and disposed between said shank and a line passing through said pivot axis and said catch means whereby the lower edge by said door is held closely adjacent said bed, and keeper means movably mounted on said door and releasably engag'eabie with said actuating member to hold said actuating member in an operative position with respect to said door whereby removal of said hook means from a position below said catch means ispositively prevented, the improvement comprising:

mounting plate means positioned adjacent the exterior surface of said door, said mounting plate means having said actuating member and said latch bolt pivotally mounted thereon;

retainer means positioned adjacent the exterior surface of said door and fixedly connected to said door, said retainer means including guide means coacting with said mounting plate means for limiting movement of said mounting plate means relative to said door, to a downward direction;

releasable coupling means coacting with said retainer means and said mounting plate means for normally interconnecting same to prevent said downward movement of said mounting plate means relative to said retainer means, said releasable coupling means including a coupling member movably supported on said door and extending between the interior and exterior surfaces thereof; and

manually operable release means disposed adjacent 4. The improvement according to claim 3, wherein said release means includes a lever handle mounted for swinging movement relative to said door within a substantially horizontal plane, and means coacting between said handle and said coupling means for causing disengagement of said coupling means in response to horizontal swinging movement of said handle.

5. The improvement according to claim 3, wherein said keeper means includes an engaging member mounted directly on said door and spaced from said mounting plate means, and connecting means coacting between said actuating member and said engaging member when said latch bolt is disposed below said catch means for maintaining said lock structure in a latched position, said connecting means permitting said mounting plate means to move relative to said retainer plate means when said coupling means is disengaged while preventing said mounting plate means and the actuating member and latch bolt mounted thereon from being completely disconnected from said door.

6. The improvementaccording to claim 5, wherein said engagement member is pivotally mounted on said door adjacent the exterior surface thereof, and wherein said actuating member comprises an elongated handle having the free end thereof disposed closely adjacent and coacting with the pivoted engaging member when said lock structureis in a latched position, and wherein said connecting means is connected between the engaging member and the handle adjacent the free end thereof for preventing total separation thereof.

7. The improvement according to claim 6, wherein said release means includes a lever handle mounted for swinging movement relative to said door within a substantially horizontal plane, and means coacting between said handle and said coupling means for causing disengagement of said coupling means in response to said swinging movement of said handle; 

1. A door lock structure for an upwardly acting door of a truck van, comprising: latch means mounted on said door adjacent one side thereof, said latch means including mounting plate means disposed adjacent said one side of said door, and an actuating member and a latch bolt pivotally mounted on said mounting plate means; said latch means further including retainer means fixedly secured to said door adjacent said one side thereof, said retainer means having means having integral guide means positioned for engagement with said mounting plate means for preventing movement of said mounting plate means relative to said retainer means in all directions except downwardly; catch means adapted to be mounted on the bed of a truck and positioned for engagement with said latch bolt when the lower edge of said door is adjacent said bed and said catch means; releasable coupling means movably carried by said door for normally connecting said mounting plate means to said door, said releasable coupling means being normally positioned for holding said mounting plate means against said downward movement when said mounting plate means is in said position of engagement with said guide means; release means accessible only from the other side of said door and connected to said coupling means for selectively disengaging said coupling means from said mounting plate means to disconnect said mounting plate means from said door, whereby said door may be moved toward an open position without prior disconnection of said latch means from said catch means, said release means including a lever handle pivotally mounted at said other side of said door and disposed for swinging movement within a plane substantially perpendicular to said door; and means loosely and securely connecting said latch means to said door after said mounting plate means has been released from said door.
 2. A door lock structure according to claim 1, wherein said releasable coupling means comprises a pin slidably carried by said door and extending therethrough, said retainer means and said mounting plate means having aligned apertures when said mounting plate means is in said position of engagement by said retainer means, one end of said pin being positioned to normally pass through said aligned apertures for interconnecting said mounting plate means with said door, and said handle being pivotally interconnected near one end to the other end of said pin, said handle having cam means formed on the one end thereof and disposed for engagement with said other side of said door for retracting said pin from said aligned apertures in response to said swinging movement thereof from a first position disposed substantially parallel to the inner surface of the door to a second position disposed substantially perpendicular to the inner surface of the door.
 3. In a truck van having a bed and an upwardly acting door, and a door lock structure coacting between the door and the bed, the door lock structure having an actuating member pivotally mounted on the door near the lower edge thereof for movement about a substantially horizontal pivot axis, a latch bolt pivotally supported upon the door for movement with respect to said actuating member, said latch bolt having a shank and an elongated arcuate hook means extending sidewardly from the shank and adapted to extend below the lower edge of said door, the center of gravity of said bolt being near said shank, the radially inner surface of said hook means near the free end thereof being spaced radially from the latch bolt pivot axis by a distance slightly greater than the opposite end of said surface, catch means mounted to said bed below said pivot axis and arranged for snug engagement by said surface of said hook means while said center of gravity is spaced from and disposed between said shank and a line passing through said pivot axis and said catch means whereby the lower edge by said door is held closely adjacent said bed, and keeper means movably mounted on said door and releasably engageable with said actuating member to hold said actuating member in an operative position with respect to said door whereby removal of said hook means from a position below said catch means is positIvely prevented, the improvement comprising: mounting plate means positioned adjacent the exterior surface of said door, said mounting plate means having said actuating member and said latch bolt pivotally mounted thereon; retainer means positioned adjacent the exterior surface of said door and fixedly connected to said door, said retainer means including guide means coacting with said mounting plate means for limiting movement of said mounting plate means relative to said door, to a downward direction; releasable coupling means coacting with said retainer means and said mounting plate means for normally interconnecting same to prevent said downward movement of said mounting plate means relative to said retainer means, said releasable coupling means including a coupling member movably supported on said door and extending between the interior and exterior surfaces thereof; and manually operable release means disposed adjacent the interior surface of said door and accessible solely from the interior of said truck van, said manually actuatable release means being interconnected to said coupling means for permitting manual release of same to disconnect said mounting plate means from said retainer means to thereby permit said mounting plate means to move downwardly relative to said retainer means.
 4. The improvement according to claim 3, wherein said release means includes a lever handle mounted for swinging movement relative to said door within a substantially horizontal plane, and means coacting between said handle and said coupling means for causing disengagement of said coupling means in response to horizontal swinging movement of said handle.
 5. The improvement according to claim 3, wherein said keeper means includes an engaging member mounted directly on said door and spaced from said mounting plate means, and connecting means coacting between said actuating member and said engaging member when said latch bolt is disposed below said catch means for maintaining said lock structure in a latched position, said connecting means permitting said mounting plate means to move relative to said retainer plate means when said coupling means is disengaged while preventing said mounting plate means and the actuating member and latch bolt mounted thereon from being completely disconnected from said door.
 6. The improvement according to claim 5, wherein said engagement member is pivotally mounted on said door adjacent the exterior surface thereof, and wherein said actuating member comprises an elongated handle having the free end thereof disposed closely adjacent and coacting with the pivoted engaging member when said lock structure is in a latched position, and wherein said connecting means is connected between the engaging member and the handle adjacent the free end thereof for preventing total separation thereof.
 7. The improvement according to claim 6, wherein said release means includes a lever handle mounted for swinging movement relative to said door within a substantially horizontal plane, and means coacting between said handle and said coupling means for causing disengagement of said coupling means in response to said swinging movement of said handle. 